Optical tellurite glasses for optical waveguide amplifiers and oscillators, and process for producing them

Abstract

The present invention relates to optical tellurite glasses for optical waveguide amplifiers and oscillators, and process for producing them. The object was to provide, with a high yield, optical tellurite glasses for oscillators and optical waveguide amplifiers in planar and fiber form which have good melting and processing properties and a high crystallization stability and a low water content. This is achieved by a special glass composition (mol %): TeO 2 :  65-78 ZnO:   2-23 PbO:   1-23 (where total ZnO + PbO   15-25) Nb 2 O 5: 0.5-12 La 2 O 3 and/or other rare earth oxides: 0.2-8  (where total Nb 2 O 5 + La 2 O 3  0.7-16) Metal halides: 0.5-3  where the components of the glass composition are mixed without water and hydrogen and are melted in a dry oxygen stream. Their good properties means that the tellurite glasses can be used as optical waveguides in the form of planar and fiber structures, optical waveguide amplifiers and laser glasses.

1 . Optical tellurite glasses for optical waveguide amplifiers and oscillators, having a composition (mol %, based on oxide) of:  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   TeO 2 : 
                    65-78 
                 
                     
                   ZnO: 
                     2-23 
                 
                     
                   PbO: 
                     1-23 
                 
                     
                   (where total ZnO + PbO 
                     15-25) 
                 
                     
                   Nb 2 O 5:   
                   0.5-12 
                 
                     
                   La 2 O 3  and/or other rare earth oxides: 
                   0.2-8  
                 
                     
                   (where total Nb 2 O 5  + La 2 O 3   
                    0.7-16) 
                 
                     
                   Metal halides: 
                    0.5-3.  
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
                
                
                
               
            
           
         
       
     
     
         2 . Optical tellurite glasses according to  claim 1 , characterized by the following additional constituents (mol %, based on oxide):  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   Al 2 O 3 : 
                   0-5 
                 
                     
                   Ga 2 O 3 : 
                   0-5 
                 
                     
                   Ta 2 O 5 : 
                    0-10 
                 
                     
                   Li 2 O: 
                   0-8 
                 
                     
                   Na 2 O: 
                    0-10 
                 
                     
                   K 2 O: 
                   0-8 
                 
                     
                   MgO: 
                   0-8 
                 
                     
                   BaO: 
                    0-12 
                 
                     
                   Y 2 O 3 : 
                   0-5 
                 
                     
                   WO 3 : 
                    0-10 
                 
                     
                   In 2 O 3 : 
                   0-6 
                 
                     
                   Bi 2 O 3 : 
                   0-5 
                 
                     
                   GeO 2 : 
                   0-5 
                 
                     
                   P 2 O 5 : 
                     0-10. 
                 
                     
                     
                 
                     
                     
                 
             
                
                
               
               
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
           
         
       
     
     
         3 . Optical tellurite glasses according to  claim 1 , characterized in that the metal halides used are metal chlorides and/or fluorides, such as PbF 2 , ZnF 2 , PbCl 2  and ZnCl 2 .  
     
     
         4 . Optical tellurite glasses according to  claim 1 , characterized in that the La 2 O 3  is partially or completely substituted by the other rare earth oxides, such as Er 2 O 3 , Tm 2 O 3 , Ho 2 O 3 , Yb 2 O 3 , Pr 2 O 3 , Dy 2 O 3  and/or Nd 2 O 3 .  
     
     
         5 . Optical tellurite glasses according to  claim 4 , characterized in that the other rare earth oxides, such as Er 2 O 3 , Tm 2 O 3 , Ho 2 O 3 , Yb 2 O 3 , Pr 2 O 3 , Dy 2 O 3  and/or Nd 2 O 3 , are admixed with the La 2 O 3  in a concentration of 0.005-5 mol %.  
     
     
         6 . Process for producing the optical tellurite glasses according to one or more of the preceding claims, characterized in that the components of the glass composition are dried, preferably at approx. 400° C., and are substantially free of water and hydrogen, and are mixed and melted in a dry oxygen stream, preferably for at least 90 min, at a maximum temperature of 950° C. with stirring.  
     
     
         7 . Process according to  claim 6 , characterized in that substantially water-free compounds, such as oxides, nitrates, carbonates, sulphates, phosphates and halides, are used as components of the glass composition.